Air sampling means



Feb. 19, 1963 H. FROEHLICH ETAL 3,

' AIR SAMPLING MEANS Filed Feb. 10, 1960 3 Sheets-Sheet 1 1514x0121; z".morillzl m R061??? A, KIZZ 302K410 E MELTO fizzy ATTORNEY F b 19 19 3H-v E. FROEHLICH ETAL 3 077 779 AIR SAMPLING MEANS Filed Feb. 10, 1960 5Sheets-Sheet 2 '55 52 64 l K0dEKA.7ZZEK,

ATTORNEY 19, 1963 H. E. FROEHLICH ETAL 3,077,779

AIR SAMPLING MEANS Filed Feb. 10, 1960 5 Sheets-Sheet 3 rrq; 6'.

F mamzrmmim; IUU 9 Roam Airzzzza INVENTORS ATTORNEY ttes This inventionrelates to the sampling of high altitude atmospheric air.

It is an object of the invention to provide improved apparatus andtechnique for collecting an uncontaminated air sample at high altitudeambient pressure and bringing the sample to earth, where the sample maybe conveniently analyzed.

Another object is to collect a relatively large air sample at thecollection altitude and ambient pressure in a large container, transferthe sample to a relatively small container capable of withstandingground impact and abrasion, and deliver the latter container intact toearth.

A further object is to provide an improved container for delivering thesample to earth.

Additional objects and advantages of the invention will appear as thedescription proceeds.

The invention will be better understood on reference to the followingdescription and the accompanying more or less schematic drawing,wherein:

FIG. 1 shows a balloon system embodying features of the invention, justas it is launched or in an early stage of its ascent.

FIG. 2 shows the system at ceiling altitude just as the collection ofthe sample has been completed.

FIG. 3 shows the descending system when the sample has been completelytransferred to the delivery vessel shortly before ground impact.

.FIG. 4 shows circuitry for controlling the various squibs, valves, andblowers.

FIG. 5 is an elevational view taken at 5--5 in FIG. 4.

FIG. 6 is a fragmentary elevational view of a tube from which the linerof the delivery vessel may be formed.

FIG. 7 is a fragmentary elevational view of a tube from which the middleor outside layer of the delivery vessel may be formed. FIG. 8 is a view,partly in section and partly in elevation, showing the delivery vesselas it appears when fully inflated, the seams and the gathering at thetops and hottoms of the three layers being omitted for the sake ofsimplicity. FIG. 9 is a fragmentary top plan view taken at 9-9 in FIG. 8and showing the gathering of the material but omitting the seams.

FIG. 10 is an enlarged fragmentary sectional view taken at ill-10 inFIG. 9 to show the gathering of the material at the ends of the deliveryvessel.

. Referring now more particularly to the drawing, disclosing anillustrative embodiment of the invention, there is shown at 10 a balloonsystem including a tow vehicle such as a balloon envelope 12 having aport 13 (FIG. 4) controlled as by a lift gas escape hatch l4 biasedtoward open position by a spring 16 but held closed by a cord 18 passingthrough a squib 20.

A load line 21 suspended from the envelope 12 passes through a squib 22and in turn suspends a parachute 23. Suspended from the parachute 23 bya load line 24 is a discharge valve 25 secured as at 26 to the top of aninelastic flexible air sample delivery vessel or compartment 27 whosedetails will appear as the description proceeds. The ends of the vessel27 are connected by a load support assembly 23 (FIG. 8) within thevessel. A housing 3,d77,779 Patented Feb. 19, 1963 29 secured as at 3!}to the bottom of the vessel 27 contains a transfer blower 31 (FIG. 4),preferably of the axial type, and a valve 32 comprising a gate 33 biasedby a spring 34 toward closed position but held open by a cord 35 passingthrough a squib 36. The housing 29 is connected at 37 to the top of anair sample collector or compartment such as the film bag 3S. Aperforated hose $9 is suspended from the top of and extends asubstantial distance down in the collector bag 38 to prevent the blower31 from sucking the film material of the bag and thus to preventinterference with flow from the bag to the vessel 2'7. The hose 39 is ofa character which may flex but will not collapse to the extent ofshutting off flow therethrough.

A housing 4i) for a valve 41 is connected as at 42 to the bottom of thecollector 38. The valve 41 comprises a gate 43 biased by a spring 4-4toward closed position but held open by a cord 45 passing through asquib 46. A preferably centrifugal type collector blower 47 for drivingthe sample from the high altitude atmosphere into the collector 38 isconnected as at 4-8 to the bottom of the housing 4%, and has anatmosphere inlet 50, providing a seat for the gate 51 of a valve 52, thegate being biased by a spring 53 toward open position but held closed bya cord 54 passing through a squib 55.

Suspended from the blower 47 as by a line 56 is a housing 57 for thepower supply, squib and blower controls, and a radio beacon (not shown)enabling the system 10 to be tracked.

A low pressure aneroid bellows switch 60 has an arm 62 connected viabattery 64 to ground and arranged to sweep over a strip 66 having acontact 68 connected to the squib 55 and also to a timer 7% having agrounded hand 72 adapted to complete a cycle in a predetermined period.The timer dial 74 has a contact 76v elongated in the direction of sweepof the hand 72 and connected via a battery v78 to the blower 47. Beyondthe contact 76 in the-sweep of the hand 72, the dial 74 has a contact 30connected via a battery 82 to the squib 46 and also to the squib 20.

A delayed double action high pressure aneroid bellows switch 86 has anarm 88 connected via a battery 90 to one terminal of the transfer blower31 and is adapted to sweep over a strip 92 having a contact 94 connectedto the other terminal of the blower. The arm 88 is also connected viathe battery 90 to one terminal of the squib 36 whose other terminal isconnected to a second contact 98 on the strip 92. As the balloon system19 (FIG. 1) ascends, the arm 83 rides on a bar 100 which is attached atone end 102 at the low altitude end 104 of the strip 92; at an altitudeabove that at which engagement between the arm 88 and the contact 94 canoccur, the arm will snap oil the free end 106 of the bar and onto thestrip; thereafter the arm will ride along the strip and eventually,pursuant to descent of the system, successively engage the contacts 94and 98.

The balloon load line squib 22 is connected in series with a battery 110and a mercury switch 112.

The envelope 12 having been inflated to the extent 116C? essary to carrythe system 10 at or approximately at the desired rate of climb and tothe predetermined high ceiling altitude at which a sample of theatmosphere is to be cap tured, the system is launched. The inflation canbe carried out in any suitable way known in the art. For this purpose,for example, the envelope 12 could be provided with an inflation tube116 communicating at its upper end with the interior of the envelope,and the nozzle of a hose from a lift gas supply (not shown) introducedinto the open lower end of the tube and then removed when inflation isstopped, whereupon the tube may be tied closed as at 118. At launching,the system 10 has the appearance shown more or less schematically inFIG. 1, the envelope 12 being slightly inflated (with its inflationbubble); the vessel 27 and the collector 38 evacuated and accordinglycollapsed; the balloon envelope lift gas escape hatch 14, the dischargevalve 25, and the collector blower inlet valve 52 being closed; thecollector blower outlet valve 41 and the transfer blower valve 32 beingopen; the timer switch hand 72 being at its starting position (FIG. 4);the bellows arm 62 being at its ground altitude position (upper endportion of contact strip 66, FIG. 4); the bellows arm 88 being at itsground altitude position off the strip 92 and in engagement with the bar100 near the strip end 104; and the mercury switch 112 being open (FIG.4).

When the ascending system reaches a predetermined alitude which isslightly below ceiling (collection) altitude, the bellows arm 62 engagesthe contact 68 to close the switch 60, firing the squib 55 and therebyallowing the collector blower inlet valve 52 to open. Any air enteringthe collector 38 by virtue of the opening of the valve 52 will be ofslight volume and will be so close in character to that of the air atcollection altitude as to have no appreciable effect on the quality ofthe collected sample as a whole. If desired, the valve 52 could beopened when collection altitude is reached.

Closing of the switch 60 also starts the timer 70 and accordingly thehand 72. When a predetermined period has elapsed, the hand 72 reachesthe contact 76, starting the collector blower 47. This period is ampleto insure that the system 10 is at collection altitude when the blower47 starts, as the rate of climb of a given balloon system cannot alwaysbe accurately predicted.

The collector blower 47 proceeds to draw air from the ceiling altitudeatmosphere and drive the air into the collector bag 38. The hand 72continues in engagement with the contact 76 for a sufficient length oftime to enable the bag 38 to be filled with the desired volume of air atthe ambient pressure. As a safety factor, the bag 38 is made oversize topreclude full inflation as otherwise the bag might burst.

When the desired volume of air has been collected in the bag 38 (FIG.2), the hand 72 sweeps free of the contact 76, thus opening the circuitfor the blower 47, which accordingly stops.

Promptly thereafter the hand 72 engages the timer contact 80, firing thesquib 4-6, thus severing the cord 45, whereupon the collector bag inletvalve 41 snaps closed to prevent escape of the collected air sample fromthe bag 38. This engagement with the contact 80 also fires the squib 20,thus severing the cord 18, enabling the balloon envelope hatch 14 tospring open and thus allowing lift gas to escape from the envelope 12through the port 13 and thereby initiate descent of the balloon system10 and opening of the parachute 23. The rate of the descent will ofcourse increase until the bottom level of the lift gas in the envelope12 has risen to such an extent that no more of the lift gas will escapefrom the envelope port 13 (FIG. 4), whereupon the descent will stabilizeat a predictable rate.

The contact 68 is of such extent along the strip 66 as to insuresustained engagement with the switch arm 62 at least until the hand 72engages the contact 80. The port 13 is of predetermined size andlocation above the bottom of the envelope 12 to insure against soprecipitate a drop from ceiling alitude as could operate to rupture theenvelope, yet provide suflicient rapidity of descent to insure that thearm 62 will have separated from the low altitude end of the contact 68so that the timer 70 will stop before the hand 72 can again reach thecontact 76.

As the balloon system 10 descends, the captured air sample in the bag 38is progressively compressed by the increasing ambient atmosphericpressure. Due to inertia, the natural tendency of the bag 38 tocollapse, the dynamic pressure of the ambient air against the lower partof the bag, and the solar heat which warms and therefore tends to renderthe sample less dense than the ambient air, part of the sample is movedinto the vessel 27, and the bag becomes increasingly slack.

With descent of the system 10, the switch arm 88, now riding on thestrip 92 toward the low altitude end 104 of the strip, comes intoengagement with the contact 94 at a predetermined lower-than-ceilingaltitude, closing the circuit for and starting the upper blower 31,which proceeds to transfer additional sample air from the collector bag38 to the vessel 27, thus further collapsing the bag. The arm 88 firstengages the contact 94 at a sufiiciently high lower-than-ceilingaltitude, and the altitude range of the contact and the stabilized rateof descent are such, that the engagement will continue until the vessel27 is fully inflated while the system 10 is aloft (FIG. 3) and the airin the vessel is at a pressure of several inches of water to give thevessel a cylindrical shape. On disengagement of the arm 88 from the lowaltitude end of the contact 94, the circuit for the blower 31 is opened,stopping the blower, and the arm comes into engagement with the contact98 to fire the squib 36 and thus sever the cord 35, enabling the spring34 to close the valve 32 and thereby seal the air sample in the vessel27. At this stage the system 10 is still aloft, although prefer-ablyrelatively close to earth.

The balloon system 10 continues its descent and, on impact of thehousing 57 with the ground, the mercury switch 112 will tilt or tumbleand close, closing the circuit for and firing the squib 22, thussevering the envelope 12 from the remainder of the balloon system. Ifthis were not done, the envelope 12 would act as a sail on the groundand thus drag the remainder of the system along the ground. Thedischarge valve 25 can then be opened by a member of the ground crew orother person to enable the air sample to be removed from the vessel 27for analysis.

The parachute 23 prevents overspeed of the final descent and also servesas a safety precaution to lower the load gently in the event of failureof the balloon vehicle 12. Th s factor is particularly important as theload could weigh up to or over 500 lbs.

. Since the bag 38 is not appreciably stressed in use, and

lightness in weight is desirable as noted above, it can be made of thin,light weight film without reinforcement and can be inexpensivelyconstructed, for example of polyethylene or other suitable plastic orother film, and is therefore an expendable item. Accordingly, oncehaving served its purpose, any damage which the collector 38 may undergoon impact or abrasion with trees, stones, or other ob ects, or theground, is unimportant. Moreover, in order to contain an ample volume ofair at the low pressure encountered at the collection altitude the bag38 must be so large that reinforcing it to withstand impact and abrasionwould add considerably more weight and expense than is involved with useof the delivery vessel 27, and would also render the system so bulky asto make launching more difiicult.

Inasmuch as the captured air sample must arrive uncontaminated, it isessential that the vessel 27 be made sufliciently rugged to withstandthe rigors of ground impact and abrasion. Furthermore, to hold down thesize and therefore the expense of the envelope 12 and the quantity ofhelium or other lift gas used, and the inflation time, and to facilitatelaunching, the load should be made as light in weight as is feasible,and this is a factor in the design of the vessel 27 as well as thecollector 38, and the size and strength of the envelope. The vessel 27in accordance with the invention is preferably so constructed that, whenfully inflated, it takes the form of a cylinder preferably having aheight equal to its diameter for optimum volume-to-weight ratioconsistent with low manufacturing cost. A spherical shape would ofcourse afford a maximum volume-to-weight ratio, but the difference is sosmall (about 22%) and the fabrication cost for a sphere so greatcompared to that for a cylinder that the cylinder having theaforementioned shape is much to be preferred.

The increase in weight of the system due to the addition thereto of theair sample will be offset by the buoyancy added by the sample, so thatthere will be no net increase in the weight of the system providedtemperatures inside and outside remain equal.

Let it be assumed that an air sample which is to have a ground levelvolume of 1200 cu. ft. at ground atmospheric pressure is to be collectedat an altitude of 80,000 ft., and that the transfer of the sample fromthe collector 38 to the vessel 27 is to be commenced when the system hasdescended to 30,000 ft. and completed at an altitude of 3000 ft. Thecollector 38 should then have a volumetric capacity of at least about33,000 cu. ft, since that is the approximate volume of the sample at analtitude of 80,000 ft. The vessel 27 should have a volume of about 1300cu. ft., since that is the approximate volume of the sample at analtitude of 3000 ft. For the purposes noted, the volume of the vessel 27should be such that, when the blower 31 stops, the air in the vesselwill be at a pressure slightly above the ambient pressure at 3000 ft.

For the example given, it would be suitable to arrange for the switcharm 62 to come into engagement with the contact 68 at an altitude of75,000 ft.; the hand 72 to have a cycle of 60 minutes; a period of 20minutes to elapse before the hand engages the contact 76; the hand toremain in such engagement for 30 minutes; the descent to stabilize atabout 60,000 ft.; and the switch arm 88 to come into engagement with thecontact 94 at an elevation of 30,000 ft. Of course, for this example,the switch arm 88 will come into engagement with the contact 98 when thesystem has descended to 3000 ft.

If the vessel 27 were rigid, the sample therein when sealed at 3000 ft.would arrive on the ground with its volume unchanged, so that thepressure of the sample in the vessel when at rest on the ground would beabout 940 millibars, whereas the ambient pressure, if at sea level,would be 1013 millibars. The vessel 27 being collapsible, however, itwill, when on the ground, confine the sample at essentially the ambientground atmospheric pressure, so that the sample therein will be at theground atmospheric pressure.

The vessel 27 preferably comprises an air-impervious inelastic flexiblesheet liner 120, an air-pervious impact and abrasion resistantintermediate inelastic flexible sheet layer 122, and an air-perviousimpact and abrasion resistant inelastic flexible sheet casing 124. Aliner 120 of polyethylene film, having a thickness of 2 /2 mils, wouldbe satisfactory. The layer 122 should be tough, and a rough nylon wovencloth, having a tensile strength of 100 lbs. per inch, would besuitable. The casing 124 is preferably a solar radiation-resistantimpregnated cloth, for example a neoprene-impregnated nylon cloth, suchas Fiberthin, or it could be of unimpregnated material such as the layer122. Unless the layer 122 and casing 124 are air-pervious, air might betrapped in chambers between them or between either of them and the liner120. Such air, expanding with ascent of the system 10, could rupture thevessel 27 and enter the interior of the vessel, thus contaminating thesample to be collected. The rupturing force and contamination could besubstantial, consiclering the fact that at, say, a collection altitudeof 80,000 ft., the trapped air would have or tend to have some 28 timesthe volume it occupied at ground level.

The liner 120 is formed of a tubular member 126 (FIG. 6) which maycomprise rectangular panels 128 heat-sealed continuously throughouttheir lengths as indicated at 130. Each end of the tube is gathered, andthe resulting central portion is wrapped about a metal or other suitablering 132 (FIG. 8) and heat-sealed as at 134 in a continuous circle aboutthe ring periphery. The load support assembly 28 comprises a suspensioncable 136 linked as at 138 at each end to diametrically opposite eyes140 having stems passing through the inner part of the liner portion andthreaded into the ring 132.

The layers 122 and 124 are each formed from a tubular member (FIG. 7)which may consist of rectangular panels 6 stitched together throughouttheir lengths as at 142; Each end of the tubular member is gathered asin the case of the tube 126, in any suitable fashion such as indicatedat 144 (FIGS. 9 and 10), but to provide a reduced end opening 146 (FIG.8), and there stitched as at '148.

The casing 124 is equipped with a longitudinal zipper 152 (FIG. 8)providing apassage enabling the layer 122 to be assembled within thecasing, and the layer 122 has a like zipper 154 positioned directlybehind the zipper 152 to provide therewith a passage enabling the linerto be inserted into the layer 122. The stitching, particularly at 142(FIG. 7), provides numerous passages through the casing 124 and layer122, and the latter is air-pervious even aside from its stitching, sothat the atmosphere is in free communication with the outside of theliner 120. The zippers 152 and 154 render the layers 122 and 124additionally airpervious.

The rings 132 are formed with additional tapped holes (not shown) forthe reception of the bolts 26 and 30, respectively.

As noted above, the vessel 27 is collapsible. However, when fullyinflated, the vessel 27 assumes the cylindrical shape shown in FIGS. 3and 8. The load support assembly 28 operates to insure that the vessel27 will assume a cylindrical shape when fully inflated and to relievethe vessel from stress from the remainder of the load train.

The pair of layers 122 and 124 is preferred to a single thick outsidelayer because of the greater resistance to penetration by a thorn,barbed wire, or other sharp object. Such an object gaining entrance to asingle thick layer will pass through to the liner more readily than willbe the case if the object must enter a second protective layer. The factthat the protective layers 122 and 124 are not bound together in themanner of laminations promotes the resistance to penetration to theliner.

While preferred constructions and operations are herein described insome detail, they should not be regarded as restrictions or limitations,as many changes may be made in construction and arrangement of partswithout departing from the spirit and scope of the invention.

We claim:

1. In an apparatus for sampling high altitude atmospheric air,

a flexible vessel adapted to be parachutcd to the ground;

said vessel having an opening at one end for the reception of anatmospheric air sample at high altitude; said vessel comprising anair-impervious inelastic flexible film liner;

said vessel also comprising flexible relatively tough envelope meanssecured to and embracing the liner for protecting the liner from rupturedue to ground impact and abrasion;

the envelope means being air-pervious to preclude entrapment of airbetween the envelope means and the liner;

the envelope means being equipped with zipper means to enable the linerto be readily inserted in the envelope means preparatory to theirsecurement;

the zipper means being air-pervious.

2. In an apparatus for sampling high altitude atmospheric air,

a flexible vessel adapted to be parachutcd to the ground;

said vessel having an opening at one end for the reception of anatmospheric air sample at high altitude; said vessel comprising anair-impervious inelastic flexible film liner;

said vessel also comprising flexible relatively tough envelope meanssecured to and embracing the liner for protecting the liner from rupturedue to ground impact and abrasion;

the envelope means being air-pervious to preclude entrapment of airbetween the envelope means and the liner;

the envelope means being equipped with zipper means References Cited inthe file of this patent UNITED STATES PATENTS Grimm May 5, 1959 8Iewet't Sept. 29, 1959 Lewis Dec. 1, 1959 Melton July 5, 1960 SchwoebelAug. 30, 1960 Yost Aug. 30, 1960 Smith Apr. 4, 1961

1. IN AN APPARATUS FOR SAMPLING HIGH ALTITUDE ATMOSPHERIC AIR, AFLEXIBLE VESSEL ADAPTED TO BE PARACHUTED TO THE GROUND; SAID VESSELHAVING AN OPENING AT ONE END FOR THE RECEPTION OF AN ATMOSPHERIC AIRSAMPLE AT HIGH ALTITUDE; SAID VESSEL COMPRISING AN AIR-IMPERVIOUSINELASTIC FLEXIBLE FILM LINER; SAID VESSEL ALSO COMPRISING FLEXIBLERELATIVELY TOUGH ENVELOPE MEANS SECURED TO AND EMBRACING THE LINER FORPROTECTING THE LINER FROM RUPTURE DUE TO GROUND IMPACT AND ABRASION;